Looking for information on these led displays

I am not sure if I am allowed to post regarding led display, but I am desperately looking for the information on the led displays.

1) 4 digit 7 segment green led (36mm x 11mm x 5mm)



2) This may not be led, 9 magnifying lens but can see only 6 set of 7 segments. (50mm x 18mm x 6mm)



Thanks in advance.

-- DJP

DJ,
The photos were awful.

What might help is if you find a p/n on the side of the part. Then type that number into a google search. Very often I am faced with a failed part and no cross reference.

That trick has worked well over the years.

For what it's worth, the top one looks like a clock display, and the bottom one from a 20 year old calculator.

Much luck dude
Jack Crow in Iraq

Sorry about the photo quality. I used palm camera in a rush to get the posting, couldn't get better.

The upper led is indeed supposed to be meant for the clock, but I am trying to use it to display the voltage for the new bench power supply I made. The dots at the sides are controlled individually with a common ground, but the 4 digit 7 segments seems totally different and can't get any meaningful display out. I suspect it may have some bcd conversion within it (hope so).

After reading your post, the second display looks like those green color display used by the old calculators. I can actually see the filament on the 7 segment digit. I like that color and brightness compared to the led display, but it seems I can't make use of it. I suspect I need to drive with a higher voltage?

Thanks,

-- DJP

PS.
There is no part number or any print on the display unit, no luck. I am still hoping to get some hint from the experienced users.

One thing to do is to use a "diode check" feature of a good meter to determine where the diodes are. You will need to connect the black lead to one wire, and touch the read lead to EVERY OTHER WIRE in turn. Look for the lowest voltage drop. This should indicate an active diode connection. If you see nothing, connect the RED lead to the SAME wire and sweep all pins again. When you have done this, then move the "fixed" lead to the next pin, and sweep all remaining ones.

When you find an "active" diode, put some current into it and see what lights.

Note that displays like this will often have one or more "common" pins, either cathode or anode. Once you find that pin, you should be able to light up many segments.

This is VERY time consuming, but if you have no other way to get data, then this is it.

Only thing I can say here, is that the bottom one there is almost certainly from an old calculator. Red Leds, with the die itself elongated, so that it actually forms the body of the segments, which are then magnified by the lenses, viewing angle's not great, but the advantage over LCD's is that the display at least is visible in total darkness. A red filter window was normally used to increase the contrast a little. I have a fully operational Texas Instruments TI-1200 dating back to 1976 here which has that type of display, I believe (But could be wrong), that it's a HP part.

The other one looks like a pretty standard one (I have one here identical that I scavenged from an old car radio), should be able to find pinouts for that from someplace. Numbers on this side of this one read:
"LTC 3710 LC-F4 030" If that's of any help at all. As for the old one, you're pretty much on your own, as I haven't actually tried to get any sensible information out of the spare I have, just made sure that it actually worked.

Good luck!